This invention relates to a folding chair which readily converts into a backpack having a substantial load carrying capacity.
"Backpack" is defined as a camping pack usually made of canvas or nylon supported by a light metal frame and carried on the back. Backpacks normally have a carrying capacity of approximately 40 lbs. or more as distinct from knapsacks and tote bags that normally have a capacity in the range of 10 lbs. The present invention is both a backpack and a folding chair and performs both functions with equal facility.
An essential characteristic of an acceptable backpack is that it is comfortable when carried on the back even with a full load of 40 lbs. or more. It must be configured such that rigid frame members will not dig into the back of the carrier, and it must be properly balanced so as not to sag to the side or rearwardly away from the carrier's back. Furthermore, it must be convenient to use. The backpack of the present invention has all the above-mentioned characteristics. In addition, the backpack of this invention may easily and conveniently be converted into a comfortable chair when the main contents of the pack are removed. The following patents constitute relevant background in the field of the invention.
U.S. Pat. No. 4,687,248 discloses a tote bag that may be converted into a lounge chair. As a tote bag, its capacity is in the 10 lb. range rather than that of the backpack. As a tote bag, it is provided with handles which enable the bag to be hand carried and the device also has a single shoulder strap for alternatively carrying the tote bag on one side at waist height. The article is not a backpack nor does it have the capacity of a backpack.
U.S. Pat. No. 4,676,584 discloses a foldable beach-type chair that can be carried on the back by means of its shoulder straps, and the chair in turn has an external pack attached to it. The chair appears to have limited carrying capacity-capable of carrying less than 10 lbs. The rigid chair frame bears against the back and clearly would be uncomfortable when the device is carried on the back, especially when carrying a load.
U.S. Pat. No. 2,490,367 shows a folding chair that may be collapsed and carried by handles which are attached to it, and the sides of the seat and back may be attached so that the collapsed chair may serve as a hold-all. The device has limited carrying capacity as it has no depth and could not be comfortably carried on the back.
U.S. Pat. No. 4,773,547 discloses a foldable backpack-like frame that may be opened to form a small bench-type seat. The frame in turn has a separate carrying bag. This frame would be uncomfortable in the region of the lower back of the carrier as it has a rigid frame member that extends across the lower portion of the torso when the device is placed on the back and supported by shoulder straps.
U.S. Pat. No. 4,530,451 also discloses a storage bag attached to a foldable chair frame and is uncomfortable for the same reason as the structure of the '547 patent. Another pack is shown in U.S. Pat. No. 3,266,686, which utilizes chains and pivotal links to create a chair from a backpack frame.
U.S. Pat. No. 4,487,345 shows yet another folding (typically wood frame) chair with a container attached to its back. This device would also be uncomfortable when carried on the back because of the configuration of the rigid frame.
U.S. Pat. No. 4,577,901 discloses a folding chair with carrier straps, and a cushioning pad to minimize discomfort to the lower back of the person carrying the chair. It obviously lacks the carrying capacity of a backpack.
U.S. Pat. No. 3,307,758 shows a backpack and a back rest in combination which includes ropes to hold the seat back together in proper supporting position. It is not a chair and does not support the occupant off the ground.
U.S. Pat. No. 3,662,932 discloses a box-like pack which converts to a stool. The frame includes components that unscrew from the pack and reattach to provide legs for the stool. The rigid frame members would be uncomfortable when carried on the back.
U.S. Pat. No. 4,286,739 discloses a backpack frame which when unfolded, makes up to a chair. The back portion hangs from the side rails of the back and does not form part of the seat support. Separate straps are provided for that purpose.
U.S. Pat. Nos. 5,209,381 and 5,289,958 issued to the present applicant bath disclose a backpack convertible chair. Each includes a frame portion which is carried on the back b,y straps. The frame portion comprises a front and rear panel. Cargo is stored between the front and rear panels inside the frame. While both of these references provide a very serviceable convertible backpack assembly, neither structure has armrests on the sides when the assembly is in the chair configuration.
The present invention provides a backpack convertible to a chair assembly with arms that afford easy access and provide a person seated in the chair maximum comfort.